Release 10.1A: OpenEdge Getting Started:
Database Essentials

Database capacity

It is important to understand not only how much data is in your database today, but also how much growth to expect. On existing databases, you should first consider the storage area high-water mark. The high-water mark is established by the number of formatted blocks in an area. In an area with many empty (unformatted) blocks, data is allocated to the empty blocks before the system extends the last extent of the area. The goal is to never use the variable extent but to have it there if necessary.

Plan your excess capacity to be sufficient to at least cover your desired uptime. Each environment has a different amount of required uptime. Some systems can come down every evening, while 24x7 operations might only plan to be shut down once a year for maintenance. With careful planning you can leave your database up for long periods of time without the need for a shutdown. In most cases, the OpenEdge database does not need to be shut down for maintenance.

The operating system might need to be shut down more often than your database for maintenance or an upgrade. Examples of this type of maintenance are: clearing memory, installing additional hardware, or modifying the operating system kernel parameters. In Windows, it is generally necessary to reboot the system every 30 to 90 days to avoid problems, while on most UNIX systems once a year is more common. You must plan for growth to cover the period of uptime that is appropriate for your system.